Just picked up an 83 FB and noticed some mold in the carpet, pulled and cut the carpet and noticed the padding under both seats was wet. Moonroof is loose, any one know if theres a latch replacement or a seal repair kit?

 

Moon roof has 4 drains. 2 run soft lines down the fr A-pillars to drain into the inner fr fender. Rears drain out the rear B-pillar vent. All these soft lines fit over a nipple-extension at the roof holes. If one has come loose (which is unusual) you would need to drop part of the ceiling to access and correct.
First I would check to be sure all 4 drains are clear! I fabbed up a coat-hanger (or any small gauge stiff wire) with a hooked end, and ran it down each line.
Seal kit: there is just the main rubber gasket that runs the perimeter of the opening. If your's has never been replaced (likely) its worth buying a new one. Mazdatrix sells the OE piece. Be warned! If you pull up the gasket (just pinches onto the roof rim) you will prob find rust! Have your POR15 standing by to seal that up!
Loose?
So you mean at the rear latch assy? This is the only "hard-point". Obv you have checked the attaching screws. Has the latch failed? does it still operate?
Stu A
80GS
AZ

 

If your drain holes are clogged I'd blow compressed air through it to clear it out. There are 2 more drains for the back window, check to make sure those are clear as well.

 

So it's where the screw assy is, I can just push the moonroof and it pops up. Hoping that's just where it's leaking.

 

OR the drains could be just rusted bad enough that they leak. i have a parts car that did that. this, along with pieces of foam under the rear seat mounts, they rusted out also.

 

The latch has failed but after a hard rain today I noticed the water coming from under the dashboard on both sides basically by the A Pillar

 

My guess is that it's coming from either a rust hole down by the lower windshield trim, or a hole where the windshield wiper motors/arms are (underneath the vented panel piece).

As for the water coming in from the sunroof latch area, the water must be sitting and filling up and not draining out of the drains. After it fills up it will start to drip into the interior.