16/4 R/Arti?
Yes, but you lose the Core 18 Rogue Mech enhancement, "+1 Competence Bonus to Critical Multiplier w/ crossbows" (+2 w/ GXB's) - which is pretty darn nice.
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http://ddowiki.com/page/Mechanic_enh...Core_abilities
Now, with an 18/2, you don't get that 'til Lvl 20, so if you're only going to 20 and then immediately Reincarnating from there - meh, not as key. But most builds offered on these Forums (have to) present themselves ready for pushing thru into Epic play, which is why you see what you see.
If this is a 1st life alt, I'd advise you to do exactly that - NOT plan to push to 30, not yet. Get your 34 point build, get a PL under your belt, get some game experience, collect some better gear, maybe a crafter alt, maybe a 2nd medium-high level alt to help w/ the TR'd one - and then go for it. Ymmv, but for me (I tried it), just a bit of a slog.