Good luck. I've been in the market for an 1887 for a couple of years and have passed on a couple because of missing parts. If you look long enough you might be able to find something, but they are uncommon and expensive.
In the last five years I've seen a stock (which I'm still kicking myself for not buying just to have) and a bolt.
Is this the one on a certain auction site with the jacked up stock?
edit: I ask because they're uncommon enough that you'll spot the same one cropping up a lot, and I think I've passed on that particular one 4 or 5 times now.