Nope! Many people use Humbrol enamel as the gloss black. I would just say that I would be extra careful as Alclad is a 'hot' lacquer and if you put to much down it can attack the Humbrol. HOWEVER as the idea with Alclad is to go very lightly it should not be a problem.
Also if you don't know already, you can forget the nice and even passes left to right, as with normal paints. Just dust it on very lightly in ALL directions and WATCH all the time. The moment it looks like it is getting there, stop and have a good look.
The ONLY secret with Alclad is to know when to stop. Give it to much and the effect is lost and it just looks like any other paint.
Should you be interested, try it out on a bit of plastic. A 4 inch square of plastic card is ideal. Prime it and when dry give it the following treatment:
Paint bands as follows. leave one just primer. Then do a matt black then a glossy one. The last stripe can be any other colour you like to use as a primer. Let those dry. Cover 3/4 of the test piece and spray the exposed 1/4 the same way you normally would paint it. The next 1/4 spray with very light criss-cross strokes in all directions. The next 1/4 give it a light rub with fine wet and dry, some up and down, some left to right and spray very lightly again... the last 1/4 leave as it is so you can remember which undercoat you used.
Ian M