[FarmerPotato]

I tried giving a dictionary of "preferred recognitions" to the OCR but got no improvement.

I might do what you said, column sensitive. A first-pass assembler which does spell checking and makes the corrections. M0V is a single replacement on MOV, MOV8 is closest to MOVB. For registered, R Oh must be R zero. But R Oh will be valid as a symbol name (curse your poor choice of symbol name). Alas, R1 is defined in the symbol table as a mnemonic for 1.

This idiom occurs in TMS9900 assembly (of which I have 2100+ pages to scan)

Indexed addressing into caller's register file: MOV @R1*2(R13),R0

Where R1 is 1, a small offset in #words so the operand is pointer to the word after where R13 points. Yet @RI(R13) is valid if RI is in the symbol table.

So there has to be some heuristic that starts at "is RI a defined symbol?" "Can a symbol be used in this context?" Yes/Nope: it is probably R1.

And R11 is used a lot.

Same curse on people who used I as a counter variable in type-in programs. Countless folks typed it as a 1 in expressions before magazines got better fonts.