As kind of an "extra" in buying another pen, I got a white dot, black body Sheaffer 1750 Vac-Fil (with stainless shaft) Tucky with Lifetime, two-tone 14k gold Triumph nib, alas with no cap. Would a metal or black plastic cap be right for this pen, and what would be a decent price for it? Alternatively, what would be a decent price for this pen without the cap? TIA!