I haven't participated in Moro for a while and I noticed that the news post said no new pumpkins this year, but I have 53 (uncarved) just sitting in my vault from years past and wanted to know if using them gains me any pumpkin that I don't have (or even duplicates which I've managed several times), or do you only get certain ones during this particular Morostide? Sorry if it seems like a pretty straight-forward answer. I'm just making sure! Thanks!

There are 7 different versions of pumpkins that you can carve. I'm not sure if each type only gives the carved versions that are associated with it though, or if you can get any random carved pumpkin from any uncarved pumpkin

But it doesn't matter how old or new they are, all of the carved pumpkins are obtainable by carving the various pumpkins. You can get repeats though, so after a certain point it may be more worthwhile to you to just purchase the ones you're missing from user shops, if you're aiming to complete your collection.

The different types of pumpkins:

Link to your Pumpkin Collection so you know what you need

Some pumpkins only produce some carvings, two pumpkins, should have a chance to give out all the different carved ones.

A breakdown of Carving Pumpkins