honestly, you don't need certs. Your broker is responsible for the shares in your account, even if they are naked short shares.
I've spoken with people from freetrade, a division of ameritrade, and they are very careful when approaching the cmkx issue. I find it strange that they were so certain the shares are real, because quite simply THEY HAVE NO IDEA. They are simply going on the word of the MM they used to purchase the shares...
The only people that know for sure are UC, Roger Glenn, the DTC, and those whom are short...