sd38-2 frame help

[Green_Elite_Cab]

So the donor became a Southern highhood SD45. Good news, the shell went right on! still need to figure out headlights and pull off, paint and swap railings as well as some other detail parts. Bad news is the couplers have nowhere to screw into. Any advice here? thinking my best bet is to glue in a block of styrene on my shell where the coupler will go and drill a pilot hole. Any other ideas?

Are the new SD45 frames the same as the old ones? I'm pretty sure the RPP shells were made for the old SD45 frame, which would have had mounting holes for a coupler pocket.

I thought the Southern Hihood SD45s were part of the new run. Might have been able to save money with an older unit if they are the same on the inside.

Also, if you glue a coupler mount pad to the shell, won't you block the frame from coming out?