>>24-25
It shouldn't be very hard to find out what it was really written in. Most compilers and programming languages leave visible and less visible trails on their generated code.
Here's some examples:
In the case of assembly, the signs are that the code can be recognized as hand-written, and may contain optimizations or lack conventions a compiler would have. For example, some coders may use some instructions which are less efficient so a compiler wouldn't use them, but they save time when coding in asm (example: pushad/popad on x86, makes saving/restoring registers easier, but it means pushing them all to the stack, and almost no compiler with a register allocator worth its salt would do that. That's just an example, you can find many many more by reading code written in ASM and comparing it with compiled code.).
In the case of Turbo Pascal, the code usually lacks optimizations, and you can find certain patterns, there's also a standard library which is usually linked in and can be easily identified. The functions may follow a very clear calling convention which is almost never violated, and so on.
Too bad I can't be arsed to find a copy of Mac Classic, but if someone does have one, they should inspect the code in a tool like IDA Pro (among others) and see what they can tell.