Kits are for buying/selling and collecting, NOT for building!
If you want to build a kit design, spend an extra day and recut the parts from balsa stock - it really is not that hard then you will still have the kit(s) to sell or trade, and the next person can do the same with it.
Are they valuable? Depends on how you look at it. All out modeling stuff that is now "valuable" really is only worth the same value as when it was new. For example, your kits were $29.95 when first intro introduced and using the Comsumer Price Index for inflation, that woud be about $105 in today's dollars - about what they would sell for on eBay.
Ron Bennett