Got my response from the fine folks at BKP!
"It will match with aged white strat covers, they will look good together, but parchment is a darker finish and will not match.
I think the best option is to go for all white pickups so they match well, or possibly choose a cover to go on the humbucker, like aged nickel for example."
Thought I'd post it in case someone else had parchment single coil covers.
