While I don't work there anymore, I did their tech for 5 years...
The B-body shift position is further forward than an A-body shifter location. Also, the A-body transmission has a "valley" machined into the tail housing just forward of the shifter location to account for the torsion bar cross member rib that runs through the tunnel. On an A-body car, that rib must be cut somewhat (along with the tunnel) in order to fit a TKO. On a b-body, that cut is not necessary.
Bottom line...it will not fit correctly as a B-body specific shifter location. Contact them and see if they will work something out with you. If you can get them the transmission, it wouldn't take them very long to re-machine it to work with an A-body.....
Richard