Yes, if you do a decent job blending in the old patch, it should work. OTOH- the edge of the old patch being so close to the puncture that if not well blended in it can become a channel for escaping air.

I'd do this if I were on a tour and needed to recycle my tube stock. If at home, I might also do it, but not as a spare. My rule is anything shaky or borderline is used first, and the best are used as spares. The thinking is that if the bad one goes, I still have a spare I can count on, but if the good stuff punctures and the spare is shaky, I'm walking.