Generally, yes.Will any other company's wing fit on the backplate?
No.Do I have to use an APEKS wing?
A BP and wing usually fit together in one of two ways. 1) You can use a STA (single tank adaptor), which bolts to the BP, through holes the wing, and holds the wing in place while providing a base and cambands for the attaching the tank. Generally, the bolt holes on the BP (and the wing) are 11" OC, or the top attachment point on the BP is a bolt hole and the lower opening is a long slot (like the Apeks BP), so wings and BPs, irrespective of brand, usually fit together well; 2) you can run the cam bands through slots in the BP and in the wing (if the wing has slots in addition to bolt holes) without using a STA. The Apeks plate has two sets of upper and lower cam band slots - a more narrowly spaced set and a wider spaced set. Plus it has multiple upper bolt holes and a lower bolt slot. It would be hard to find a wing that could not be used with the plate.