Congress-watchers believe it is too early to tell whether it is appropriate - or just coincidence - that the next chairman of the House Post Office-Civil Service Committee is also an undertaker.

Rep. James M. Hanley (D.N.Y.) is due next year to take over the unit which once held supreme control over the timing, and amount, of federal and postal pay raises, and acted as the legislative big daddy for the bureaucracy.

In the past decade the role of the committee has shrunk. The 650,000 postal workers moved out of its control, into full collective bargaining on their own. Federal pay raises are now automatic. And the president, not Congress, controls the amount of them. Federal agencies that once went hat-in-hand to the PO-CS Committee now look to other Senate and House units as their protectors and benefactors.

Taking control and revitalizing the committee will be a tough assignment for James Michael Hanley who, back home in Syracuse, runs the Callahan-Hanley-Mooney Funeral Home, a fixture in the heavily Catholic-Irish college town.

Some people think the PO-CS unit will eventually shrink away to a figurehead committee generating various inconclusive investigations or giving members an opportunity to make field trips - some call them junkets - from Paris to Japan to study the workings of the government.

Hanley is due to take over the committee because Chairman Robert N.C. Nix (D-Pa.) failed to win renomination in last Tuesday's Philadelphia Democratic primary. Nix was one of only two Black committee chairmen in the House. The Other, Rep. Charles Diggs (D-Mich.) is in deep political and legal trouble.

There is sentiment in the House for abolishing the PO-CS unit and merging its duties with other committees. The Senate did it a couple of years back, creating the Governmental Affairs Committee with much broader responsibilities than its predecessor Post Office-Civil Service Committee.

House Democrats were not eager to tamper with either the District Committee or the Nix unit - both on some streamlining "hit lists" - because both were chaired by blacks. With Nix disposed of by the voters - and beaten by a young, black minister - that bit of political protection is gone for the committee.

It will be up to Hanley, a bright crowd-pleaser who has an excellent constituent service system, and is considered an expert on postal matters and small business regulations, to save the committee from either extinction or legislative impotence. More and more committees are moving into the turf once considered sacred to the PO-CS unit. It is possible that Hanley will be able to stop the jurisdictional erosion and make the chairmanship - which he does not have yet - something worth having.

National Federation of Federal Employees deserve major credit for persuading the White House to let members of Congress look at the long-buried Lyle Report. The document, worked up by the Carter transition team, alleges that at least eight top Civil Service Commission officials cooperated with the Nixon White House to give "special emphasis" to hiring of political hacks for career federal jobs.

The White House resisted earlier pressure to release the Lyle Report, on grounds that it contained unproved charges that could damage the careers of officials named. But the NFFE obtained part of the report, and the White House has reluctantly agreed to let members of Congress look at the document, provided they do not release the names of the officials cited by it.