Handguard cap question

[trlcavscout]

So I have been playing with my BCM middy that came with a triangular cap, that is the first triangle one I have had. If I want to order a 2 piece drop in quad rail setup do I have to change to a circle cap also? Looking at the descriptions on like midway etc they say the triangle cap will accommodate A1 and A2 handguards?

[BPTactical]

All of the "drop ins" I have ever dealt with will accommodate either style.