[HECnet] PDP-11 RSX corrupted tapes: any progress?

Hi, I wonder if someone has been succesful repairing the corrupted tpc images of several PDP-11 layered products that are (not)available in some sites (bitsavers and trailing-edge come to memory). IIRC there was a kind of effort to fix whatever could be fixed (the BRU format ones, specifically) reordering the mangled tape blocks in the image. More specifically, I?m looking for an usable COBOL-81 compiler. The one which is not corrupted (cobol_v4_4) is COBOL/C11, not COBOL 81, and even for hobbyist stuff, handling COBOL-74 is a PITA?