I think you're right, but to be absolutely sure, call the Lewmar Technical Rep listed on their website and ask THE SOURCE directly, then report back to us here so we'll all know.
The diffeence between the two is probably only the combination gypsy, which can be sized for European DIN / metric chain and rope, or American / English measuring system chain and rope.
And its even more complicated than that, because all 1/4" chain is not created the same, there being a wide variety of chain grades and types of chain made from 1/4" wire stock, with various metal alloys, coatings, and chain link dimensions.
Most windlasses sold in this country for our size boats use 1/4" High Test GS-40 (or Grade 40 High Test) chain, although the larger windlasses can use 5/16, 3/8, or 7/16 chain of the same grade. This chain is made of very strong steel and heavily coated by hot dipping it in molten zinc.
There are also BBB and Proof Coil grades of chain, as well as many others, but most windlasses are not designed for use with these. They are much weaker than the GS-40 chain, about 1/2 as strong, and not nearly as well galvanized or protected, and their link dimensions are different.
Most windlass manufacturers make several gypsies for each windlass they produce, to accommodate the chain an rope used in he various markets their products are sold in.
Sometimes a person will buy a windlass for cheap with the "wrong" gypsy on it, thinking they can simply change the gypsy over eassily, then the fun begins when they find out the replacement gypsy costs nearly half as much as a new windlass outright(!)
Hope this explains the sitution a bit!
Cheers!
Joe. :teeth :thup