So I picked up a lot of 20 p-channel MOSFETs from the usual eBay supplier in China, which arrived in good order. As is often the case, the SOIC chips are in snippets of tape-and-reel carrier, but this tape looked decidedly odd:

Peeling back the tape shows that the crud is just on (or perhaps inside) the tape, not on the ICs or inside the carrier pockets:

Some of those specks are dirt, some seem to be bubbles, other are just, well, I don’t know what they might be. Maybe they were having a bad day in the tape factory?
One might reasonably conclude the chips aren’t in their original carrier…
I must gimmick up a quick test to verify that the chips behave like p-channel MOSFETs, instead of, oh, solid plastic; that Fairchild logo looks a bit grotty, doesn’t it?