I was very naive when I first started and I was so psyched to start I stropped up my ebay blade and what do you know? It shave quite well. I sent it out to get honed though and it came back quite a bit better so...

Yes you might get lucky on an NOS or old barber razor 1% of the time.

Another say, 5% of the time it might be sharp enough to shave, but I guarantee you there is a world of difference between "sharp enough to shave" and "shave ready".