In most cases, you can use your mugs from previous years. As long as the chip in the bottom is still readable, they will re-activate. It is definitely worth bringing it with you and trying.
yes, as long as the machine can read the chip, you should not have any issues. We bought ours off of ebay before our first trip in 2019, used them then packed them away. Brought them back this past summer and they worked just fine.
One other question. I noticed a picture of a Freestyle machine located at Sal's at PBH. I have searched the boards, but cannot find out whether PBH has a resort mug program or not?
Definitely bring them. We brought 2 we'd bought in 2018. re-activated both on our trip last month, had several days w no issues activating each day, but on the last day, after the re-activation for the day was paid for, one mug's chip would not read. The TM just traded it out for the new mug (the HHN one.) and we kept on using the new one after that.