If I shoot 45 # in a recurve, would I shoot the same in a long bow?

Yes.

Most likely, yes. The one caveat I would throw in is it would depend on your draw length and the particular recurve. I do not know what you have but if you have a shorter length recurve and draw it past the rated draw, you could be stacking the bow and holding much more than 45#. A longbow would most likely stack less resulting in a lower holding weight at full draw. Just a thought.

In theory, it takes a little more total effort to shoot a 45# recurve that starts out with a little more tension than a 45# longbow.  In reality, there doesn't seem to be any significant difference to me.

You will not notice any difference.

Thank you all. I draw 28" and I do notice some stacking on my Bear bows and older recurves if I extend my draw very much.

Just getting back into trad bows. Shot Bear bows in the back yard for hours and hours when I was a kid in the 60's.

Looking for a good newer recurve and long bow. Going  back to the back yard and shooting for hours and hours.

Welcome back to trad archery! I still hunt/shoot older bear recurves in the back yard. As a matter of fact I just walked in the house from a 3d deer killing session with a 1975 model Kodiak Hunter. Newer isn't always better.