This is probably late, but...
Is it possible, yes, and probable too; however, don't rule out the input pinion seal on the final drive. If I had to guess, the PO knew there was a leak, and dealt with it by slapping a little sealant around the mating faces of the final drive and the shaft housing. Is that what I'm seeing? Sealant? It shouldn't be there, unless it was being used as a bandaid. But then, if you're going to dig that far to apply the sealant? Just fix it properly, ya dig?
To get the seal out: Drain the gearbox, clean the splines of the output shaft, tape the splines up (or protect it by other means), and tap the seal with a some type of screw. Take a picture, or note the depth of the seal (I can't recall if it matters with that one; some bottom out and some will keep on going). Use said screw(s) to work to grasp and remove the seal by whichever means work for you. For me, I (extremely carefully) tapped the center of the outside face of the seal with a 1/8" drill, and then shallowly sunk two Sheetrock screws. Once they were set, I used a little piece of wood as my pivot point and worked it out using a pair of vice-grips, which grabbed the heads of the screws. Installation was done by using an appropriately sized socket and gently driving it into place until it arrived to spec.
If it's the input pinion for the FD? Well, she ain't that simple, but it's not impossible either. Do some research and find the thread on this forum where the dude celebrates with some vodka, which was in the freezer. You'll know it when you find it. Everything else here is searchable, and very accurate and useful.
