U shaped mount is marked 3916864 but I had to read it with a mirror. 99% sure it's right because I read it 5 times writing it down one digit at a time from back to front. I'll update if I find it otherwise.
L brackets same part on each side 3930675
Those are the only numbers I have so far, nothing for the bolt or the rubber bushing yet. This is on a 98 and a 99 A pumped 4BTA in two different Generators.
This is my late attempt to add useful information. I'm finally seriously getting my conversions done after stockpiling parts/trucks since 2004. 1 6BTA into a 94 3500HD 4x4 (mostly done) and 4 4BT's going into 4 different straight axle GM 4x4's. Keepin busy!