Yeah, pretty much. So for your EVs, I'd go 252 Sp. Atk, 252 Speed, and the other 6 in... something. Maybe Defense? It's either that or Sp. Defense, and the latter is naturally stronger.

That's probably best. EVs: 252 Sp. Atk - 252 Speed - 6 Defense.

Now for the moveset. Crunch would definitely be good, and I'd also throw on Leaf Blade - for Sceptile, how could you not use that in a third-gen Special Sweeper set? For the third move, you pretty much have to go with Dragon Claw, I think... that's its only other decent Special attack.

Your fourth move... hrm. The only option I can think of would be Agility, to give you a little extra jump when you need it. None of the others seem well-suited to a Special Sweeper. (For some reason I thought it learned Dragon Dance, but I guess not.) Maybe a Hidden Power, but egh... I don't even remember offhand how that works with Physical/Special. I mean, I could see HP Fire/Water/Ice getting a bit of play, but... ergh. Agility seems better to me, because you shouldn't be setting up your Sweeper against massive, obvious type disadvantages anyway.

As for your hold item, you could go a few different ways. Your safest bet might be to go with a Petaya Berry, but I could see justification for a Choice Band or even a Focus Band. Probably your call on that one.

Okay! So we have:

Sceptile
@Petaya Berry/Choice Band/Focus Band
-Crunch
-Leaf Blade
-Dragon Claw
-Agility/HP Fire/HP Water/HP Ice

Bear in mind that I do not profess to be an expert or even remotely experienced. I'm just going with what feels right based on the principles I know. Follow my advice at your own risk.