LIKE THE LAST call at an all-you-can-eat buffet, the final days of the Carter administration prompted some vigorous goodie-bagging by lameduck executives with the authority to spend money for trips and grants. The bills for all this damage -- junkets, last-minute federal grants and other parting shots of largess -- may take a while to tote up, but you already know who gets stuck with the tab.

So far, the accounting includes millions of dollars spent by an assistant secretary in the Labor Department for post-election job training grants. Many of these awards went to labor unions and civil rights groups; some went to individuals and groups that supported President Carter; and some went to the assistant secretary's former firm. Nothing in the rules and regulations prohibits these kinds of transactions, since the money comes from "discretionary funds" -- which, as veteran trough-watchers know, have no official relationship to the better part of valor.

This kind of parting generosity is not unique, either. It is an old and unfortunate custom of transition that one blows his discretionary wad before signing off. It can be, of course, that some genuine benefits for the greater good accrue: One adminstration's pet projects may be no less deserving than the next. Still, fairness and the spirit of transition do suggest that departing officials shouldn't empty all the cash registers on their way out.

Worse are the junkets -- the highflying trips at taxpayer's expense that Carter appointees managed to slip in before the bell. So far, the bookkeepers are looking at the logs from Labor, Energy, Housing and Urban Development, Commerce, Interior, Agriculture and Health and Human Services, to name a few. The trips include one by former Labor Secretary Ray Marshall, who went on an around-the-world tour that took him to Paris, Tokyo and Peking; another by former Energy Secretary Charles B. Duncan, to Paris; and one by former HUD Assistant Secretary William Medina, also to Paris.

Like the last-minute grants, these trips no doubt will stand up, at least legally, as legitimate. There is no airtight way to clip the wings of lame-duck spenders. But to curb the worst of these excesses in the future, maybe there should be some prompt post-election cutoff date for federal grants over a certain amount unless personally approved and signed by a Cabinet member and some more open, advance-review procedure for the approvals of any spectacular travel plans.