BVM F-16's were never made without doors. Scale gear only and full gear doors. Sounds like you have an early Yellow kit. How about a picture so we can verify. I would hate to have you CG it only to find out it is from another manufacturer, and not BVM. There are very simple things to look at to verify. Inside the gear doors, there was a piece of 1/8 balsa molded between the fiberglass layers to ensure stiffnes in the gear door itself. This is probably the easiest to check to see if it is a BVM kit.