Hello Brian, I see, I think I got this right, that this is your first time here on WAGS. Welcome, its a pleasure to have you. :)
While I do not know for sure, perhaps someone else does, Roy maybe, your thoughts sound plausible to me on the time frame. As far as seeing a Victor without a pattern number, I have seen a lot of Victors, but to be honest with you, I don't know if they all had pattern numbers or not. Sorry, I ain't much help. :-[
It sounds like this ain't your first rodeo on this cast iron stuff Brian. What other kind of cast iron do you have? :)