Sounds like the source was lost? Sorry to hear that... At least you found the binary! I managed to recover a few of my own Atari 6502 assembler games from hard copy source printouts I'd found. That was extremely tedious, but also rewarding.
I had a box of disks that i kept for ages and then for some reason chucked them away thinking i would never need them again. Regretting it now.
