Colt Police Positive Special

I bought an old Police Positive Special, 32 20 for $50 (gutta percha handles ). This thing had lain in an old garage for who knows how many years. Very rusty, cylinder seized up, could not cock, could not do anything. I gave it a liberal soak with rust penetrator for a long time, and the cylinder has finally freed up, and it will cock. However, I cannot operate that lever to get the cylinder to "flop out". It seems to be frozen or so rusted in there as to be unoperable. Has there been an issue for these things to fail? Wanted to know before taking it to a gunsmith for a look see. I even got a box of ammo with it !