Highway 45, for example, ran from the Oklahoma State Line west of Mansfield (now AR 96) to AR 68 near Hindsville (now part of AR 295). Like many highways in Arkansas, 45 was extended, truncated and rerouted several times. Parts of 45 are now US 62, AR 59, AR 253, and AR 96.
Sometime in the 1950's (?), the signage changed. Gone were the square numbers and the State xx Road. Now it was simply Arkansas xx.
I sent a letter to AHTD several months ago asking when the changeover occurred. Answer: "We quit making those signs after 1971 when the MUTCD was changed.".
That's not the question I asked. I wanted to know when Arkansas changed from one cut-out design to another. I guess I'll have to do my own research to figure the answer to this obviously difficult question.