I've never had any corrosion issues with iron gall ink in my Meisterstucks, but does the 51 aero have any parts that would be susceptible to corrosion?
Thanks.

Sterling Breather Tube?

I once cleaned up an aero filler, the sac protector (and press-bar) of which had corroded badly due to being left in contact with ink in the barrel, and left in a drawer for years.

But the filler tube, sac guard and press bar are the only non-gold metallic parts in the 51 pen itself, so other than that you should be ok.

Older Aero 51's did have Sterling Silver breather tubes, as already stated.
Less old ones have plastic tubes, which don't corrode.
It isn't a great problem to replace a tube, so you needn't really worry. I changed a corroded one myself after advice from this board.

If all else fails, Ernesto at Parker51.com seems to sell tubes and feeds as a spare.

Regards

Richard.