The situation with this is a bit tricky, since the Pyromancer's Mask, which constitutes the majority of this trade's value, was part of a tradeback in which the Mask was initially bought by Ender for a FN Hot Horror Holiday War Paint (this has no other sales) + a Pro KS Australium Scattergun.

Sales which have items that were traded back aren't great to use because then the two people in the trade could fabricate their own prices for items in the trade and trade the items back afterwards. While the Pyromancer's Mask wasn't a direct tradeback, the fact that it was traded back still makes using its sale here iffy.

As such, it'd be better to leave this outdated until another sale occurs, but the Co-Pilot could be valued as the California Cap + Milkman + Copper's + Scattergun + War Paint to price the GBH Dark Falkirk Helm that the Co-Pilot later sold for, since in the end, that's what was ultimately traded to get the Co-Pilot from Ender in the first place.