68 Valiant Hellcat Swap

I believe what you are referring to is a Torque to Yield fastener. The main bearing cap bolts are actually Torque to Angle fasteners. Everybody has a different opinion, but I have re-used Torque to Angle fasteners before in the past with no issues.
yes, they are sometimes called torque to Angle, but they are still torqued beyond their yield point. ie the bolt is permanently stretched. It is no longer as strong and the clamping force will be less if they are reused. From my engineering perspective - they are junk after 1 use. This is a bit of info on TTY head bolts - but same concept as main cap bolts. Why should torque-to-yield head bolts be re-used
My $0.02
Jim