What little I know about putting walnut stocks on 981Ts. They are available from three places. Marlin, Midway and Numrich (e-gunparts). Numrich will have the older stocks. Translate older as cheaper.
I ordered from Numrich. Part # 1137290. It's a stock for a Marlin 781,783. It came with metal trigger guard, bullseye, butt pad and QD Swivels. $47.20, plus $9.50 shipping. I ordered my parts in June, 2009.
The stock had to be inletted for a horizontal pin, just ahead of the 900 trigger assembly. A dremel made short work of this. Some wood must be removed, where the 900 trigger block hits. I used the wifes lipstick for transferring a mark from the trigger block to the wood. The third thing is that the front trigger screw hole had to be drilled, so the rear action screw can be used.
If you call Marlin, they may send you the action screws? I got mine from Fastenal. Part nos. BHSCS 10-32 x 1 1/2 and BHSCS 1/4-28 x 5/8. I had to take a thread off of the 5/8 screw because it was touching the bolt. These screws have allen heads. They look good and you have less chance of slipping (slipping equals scratching).
A few pictures:
I hope this information is of some use to you.
Larry