Norotos & Wilcox dovetails are different size, Wilcox's is a tad smaller so they are not 100% compatible, though mostly yes. The best route is always to go with the same brand J-arm and helmet mount if speaking of dovetail mounts (which are generally great for binoculars, but to a lesser degree beneficial for monoculars like a PVS-14).
So with your current J-arm I would suggest finding a used Norotos Rhino II mount. They sell for almost nothing and are actually very good. The original black Rhino is wobbly, weighs a bit more and lacks vertical adjustments, but the new one is great for a regular J-arms and PVS-14 combo.
I actually prefer the Rhino II over dovetail mounts for monoculars. Another candidate for a mount is the Wilcox G11 that accepts the bayonet style interface of the J-arm too, but you don't gain anything over the Rhino II except looks and maybe a bit lower profile. In addition you will be out of quite a bit more of $$.
The screw-on end of your PVS-14 (I assume) is not standard. There are some other NVD housings that accept PVS-14 optics and also accept the PVS-14 J-arm, but there are almost as many arm fitting styles as there are monoculars. For PVS-14 though there are the most amount of aftermarket upgrades for mounts and arms and other accessories, but most of them are not cheap. The standard J-arm is the cheapest way combined with a Rhino II and luckily that combo is also great.
Edit: did not notice you said you might buy something else before having the funds for Gen2+/Gen3. I strongly suggest not going the Gen1 route just to waste money, put those hundreds in the bank too. I would suggest going with at least the NightGoggles.com Gen2+ PVS-14, or a used Gen3 PVS-14 (avoid Ebay, look at EE here). Used Gen3 PVS-14 market starts at around $1000 for the most lucky - and around $2000 for the better & newer units.