Personally, I'd do a range check first and foremost. If the plane checks out with proper range with the engine off and the engine running, then I'd not bother with it at all.

Yes, in theory, the antenna is tuned.

But in the real world, the tuning is only approximate. If you buy 2 RX's one on channel 12 and another on 59, they will have the same antenna length. Yet in theory they should have slightly different lengths.

If you're on a low channel, losing that 2" might actually increase your range (ok, that's a joke, I didn't do the calculation to see how many inches channel 12 vs channel 59 would actually have, probably less than 2" though)

Not only that, but most of us don't have the antenna coming out of the RX in a nice straight line either. Usually it comes out and makes a curve or two exiting the fuse and so on.

That said, if you want to fix it, I suggest you just solder on the 2" at the tip for the reasons the guys gave above. I've done antenna replacements on RX board several times, and it's a pain. I usually just solder them together where they broke (or were cut).

Also, make sure that whatever wire you use as a replacement is stranded, and has as many strands as possible. Stiff wire will fatige under engine vibration and might break. Getting high quality wire with as many strands as possible is a good idea. Fwiw, Radio Shack doesn't seem to sell anything anywhere near flexable enough, at least not around here.