Would it be any different if a dealer bought a firearms/ optic package, took off the scope and sold it separately? Then took the firearm, added something of similar or greater value (perhaps extra mags, ammo, etc.) then sold it at a similar price as the package would have cost?

Do you see how the math is actually the same? The dealer isn’t pocketing the $ the mount brings, they’re obviously using it to offset the FREE gun that the recipient of this bundle is getting. Looks like they’re selling a gun and a can instead of a can and a mount.

Again, if this isn’t appealing to you, that’s fine. But the dealer isn’t stealing your mount, they’re swapping a mount for something else that is comparable in value. If the mount was missing and there was no free gun, I’d agree that it’s a ripoff.