Look at it this way. If the auctioned cover goes for a lot of money, your cover will likely be seen as more valuable. If the auctioned cover sells for a low price, hey, you can tell people it would have gone for more if it had been pencils-and-inks. And you might be right.
There was a time when I turned away from pencil pieces, but I've adjusted my thinking. I've come across a few artists who only work in pencils and, if I wanted an original from them, that's what I was going to have to buy. When I took a deep breath and bought my first one, the artwork was beautiful; tight and finished. I now own four pencil-only covers by three different artists and I love looking at them. I don't value them any less than the inked covers I own. They certainly weren't as cheap as some of the inked covers I own.
Just as an aside, I've seen some xeroxed Kirby pencils where I much prefer the pencil work to the inked work that was published. If the pencils were still around, that's where I'd spend my money.