Option 'b' may not be a bad idea, something on the 'if it works, don't fix it' plan.

It would look better knurled and with the screwdriver slot filled in. Given that you've already restored the finish a non original pin may not be much of an aberration. Frankly, there are very few people you'll run across that know what a proper MS Take Down Model forend pin does / does not look like, and it's absolutely your rifle.

Is it possible, however, to get a 'straw' finish on that ejector and magazine release button?

LugerForums Straw Restoration

What holds the pin in place? Will an original pin still fit properly or has the tapered hole been modified?