1974 360 "L" code air cleaner options

[74magnum]

So I'm curious if someone can shed some light on the subject.

NICKS GARAGE site has a long list of air cleaners... I'm curious about this one in particular...

1974 360 4-Barrel for B-bodies. Has flap in floor that opens at full throttle to allow more air in.





How many different ones were available for the 74 360? Is this the one that is supposed to be on my 360 "L" code? Did some come with the flap door cleaner and some without?

I ask because mine currently has what looks to be the
1975-76 360 A and B-Body. No flap in bottom




What is the likelyhood that the 75-76 one is correct? Car build date was June 74...

Any light on this situation?

Thanks.