Some will, some won't. Depends on whether the jam cleat you have allows you to tie a cleat hitch on it after you jam it.

You can't leave a reefing line just jammed in the v of the jamming horn. It could come loose. That would be a pain if the aft reefing cringle came loose (the reef clew).

More importantly, your mainsail might rip if the front reefing cringle came loose (the reef tack) while the reef clew still had tension on it.

A Jamming Horn Cleat would certainly work... but it's a lot more expensive than a plain horned cleat, which will easily handle the job. This one's from www.schaefermarine.com

I personally don't even like using a cam-cleat unless it's backed up by a horn cleat. It's too easy to release it accidentally. Here's what I mean by the term cam-cleat (also from Schaefer):

Rope clutches work well, because they're not easily released by accident. But they're very expensive.