There's nothing too special there, the "re-entry" heating is not terribly significant. Basically they are dropping in from a dead stop at 62 miles. You could make a back-of-the-envelope calculation assuming no drag until it gets to about 30 miles. I get about 3500 fps which would not generate too much heat load.
The capsule does seem to hit pretty hard. Most of those intended to land on solid ground had either big airbags or terminal braking rockets like the Russians. And they all had contour couches with shock absorbers. Mercury even had an airbag for splashing down in the water.
I think the intention here was to spend the money on the rocket braking and stabilization system and the necessary controls to make that function. The capsule is likely still "putty".