Mordaunt Short 442 tweeter questions.

!. I just picked up a used pair and I'm wondering if these tweeters are ferrofluid filled? I can't find any info.

2. Is there anyone you would trust if I wanted to send the tweeters off to be checked?

BTW they really sound great. Wonderful sound staging and a great disappearing act. They do need subs and mate well with my dual 12" Unity Audio subs. I think a REL's would be better and eventually would like to try them.