I added a sling to a couple small, synthetic stock .22s. I found some help on youtube. It is pretty straight forward: mark and drill a hole, install the studs. If the stock is hollow, you should use some type of epoxy to ensure a good connection to the stock. Of course, once you do that you may not be able to take the studs back out.
There is actually quite a few youtube videos on the 88. Can't vouch for their correctness, though.