1) expiration dates on ph/ds are usually 5 years so it's very possible they were made before the ban.
2) msten wasn't specifically named in the last ban so a lot of companies are still producing ph such as msten, dmz, and 1 alpha.
I wouldn't stress over the dates on the bottle. The only way to find out for sure is to eat some of it and see what happens. It would be cool for you to post your findings so the rest of us know if this is legit or not.