In my experience it'll work fine, with a bit of a tilt towards magenta. All my packs that old look good even now. In stuff older than that (expired 1999-2003) the colors go very strange. Fun, but not everyone's idea of good. I have a bunch of packs of these vintages and am shooting them now. Your mileage may vary, of course, but I'd suggest it's worth a try.
I would give it a try. I'm still using stuff that I got back in 2015 when they were about to axe it. I only have the one Polaroid 104, given to me that year, and as of March 2020 it's still perfect.
I have some boxes that expired in 2012 and 2018. I just grabbed one of the 2012 ones and tried a shot, came out fine. I probably should have let it warm up some but as it was, looks OK.
Anything that has expired in the last 15 years I shoot at box speed with pretty consistent success. Timing is box too, but there's no harm in giving it more time if you want as FP-100c is self exhausting. Once it's fully developed it stops.
For really old FP-100c (or Polaroid 689, which is basically FP-100c in a Polaroid box back in the last 90s and early 2000s), I overexpose 1-2 stops. Once FP100c goes off the cliff and the colors go wonky it does need more light.