Some clarity:
True pre'64 M-70s are all long actions. "Classic" (CRF) M-70s made in the 1990's and later can be either short or long action.
The TBM Kit will fit short action M-70 actions very well, to include push feed short action M-70s. Of course, the stock inlet for the bottom metal will need to be modified if the original was a hinged floorplate. Winchester did make some M-70s with the four round DBM in their line in the late 1980s and early 1990s before FNH picked the design up for the SPR and PBR. TBM will fit the DBM inlet with little or no modification, as Bear 24 can attest.
A benefit to the FNH TBM is the lack of modification to the action required for the CDI assembly. The TBM is steel. This could be good or bad, depending if strength and durability is more important to you than weight. CDI takes the more common AI mags, but the FNH mags go for about $54 through Midway or Brownells.
Hope this helps.