UNC Resources Inc., the Falls Church holding company that owns United Nuclear Corp., yesterday reported a 29 percent increase in third quarter profits, but warned that fourth quarter earnings will decline despite a large non-recurring gain.

UNC earned $9.44 million (87 cents per share) on sales of $71.1 million for the third quarter, compared with profits of $7.29 million (69 cents) on sales of $64.5 million a year earlier.

President Keith A. Cunningham said, "earnings were favorably affected by substantially higher prices for our uranium," which offset higher mining cost and slower than expected increases in output.

Cunningham said that during the current quarter UNC expects to complete the sale of its interest in part of the uranium properties it owns jointly with the Tennessee Valley Authority.

Although this will result in what he called "a very substantial" non-recurring profit, UNC plans to offset that by accelerating deliveries and completing most of its lowest priced uranium contracts.

Completion of those old contracts, "cost pressure and some reduction in production" will result in "operating earnings at a reduced level from those in recent quarters," Cunningham said.

For the latest nine months, UNC earned $26.53 million ($2.43 per share) on sales of $210 million, up from $20.79 million ($1.97) on sales of $174.8 a year ago.

First half profits for the W. Bell & Co. catalog showrooms increased 41 percent, to $1.54 million ($1.54 per share) from $1.09 million ($1.10 per share), the Rockville firm announced yesterday.

Sales for the 27 weeks ended Dec. 30 grew 34 percent to $44.1 million from $33 million during a 26-week first half a year earlier, said President Walter Bell.

Since the year before, two additional Bell showrooms were opened, in Springfield Mall last September and Tysons Corner in November.

As is typical in the gift-oriented catalog showroom business, most of Bell's profits and sales were generated during the Christmas season.

Bell said that for the 14 weeks ended Dec. 30, the company's earnings amounted to $1.46 million ($1.47 per share), up 37 percent from the $1.06 million ($1.07) earned in that quarter a year earlier. Second quarter sales were $33.2 million, up 35 percent from $24.6 million a year before.

Besides its Washington area units, Bell has showrooms in Georgia and Texas, where it plans to open a third Houston store this year.

First American Bank of Maryland reported earnings before securities transactions increased 73 percent last year to $2.19 million ($2.21 per share) from $1.27 million ($1.28 per share).

Net income after securities losses was $2.13 million ($2.15) up from $1.24 million ($1.26)

An affiliate of Financial General Bankshares Inc., First American Bank, was created by the merger of Chesapeake National Bank with American Bank of Maryland. Last year's results have been restated to reflect the combined operations of the two banks.

G.J. Manderfield, president, attributed the improved earnings to a 34 percent increase in loans and a 30 percent gain in interest income.

Assets as of Dec. 31 were $275 million, up from $248 and year-end deposits climbed to $248 million from $227 million.

Owens, Minor & Bodeker, Inc., a Richmond drug and hospital supply firm, reported third quarter earnings declined to $432,000 (56 cents per share) from $456,000 (59 cents) despite an 11 percent increase in sales to $27.9 million from $25.3 million.

Higher interest rates on bank loans were the major reason for the decrease, said G. Gilmer Minor, Jr. Chairman.

For the nine months, the firm's earnings increased to $1.46 million ($1.89 per share) from $1.38 million ($1.78) as sales climbed 11 percent to $82.6 million from $74.4 million.

Smith's Transfer Corp. of Staunton, Va., reported 1978 income increased to $9.3 million ($3.69 per share) from $9.02 million ($3.59) in 1977.

The increase was the result of acquiring of MR & R Trucking Co., Smith said. Included in the 1978 earnings was a $1.39 million gain from disposal of equipment and terminals; a $1.41 million gain from those sources was reported a year earlier.

Smith's earned $3.39 million ($1.34 per share) for the fourth quarter, compared with $2.65 million ($1.06) in 1977. Revenues increased to $82.8 million from $63.2 million.

Government Employees Financial Corp. reported unaudited earnings for last year increased slightly to $3.35 million ($1.81 per share) from $3.30 million ($1.85). Earnings per share declined because there was more stock outstanding this year.

GEFCO is the consumer finance affiliate of Government Employees Insurance Co.

Continued inflation and sharply increased short-term interest rates hurt earnings, GEFCO said; interest expenses amounted to 37.4 percent of gross income in 1988, up from 34.5 percent in 1978.

President E. L. Marks said Government Employees Financial's credit volume increased 12 percent, to $238 million from $212 million and gross income grew to $40 million from $36.2 million.

Operating expenses increased to $11.6 million from $10.3 million, the provision for losses was up 2.4 percent, and interest expense jumped to $14.9 million from $12.65 million.