Questions regarding M203 grenade launcher variants

[Spartan198]

I used search, but only three topics came up with mention of the M203, and none answered my questions.

I'm having a bit of confusion about the variants of this weapon, maybe someone can answer these questions here.

M203A1 ~ There had previously been an unsourced statement on Wikipedia (we all know it's the epitome of reliability...) that the barrel was lengthened from 9 to the standard 12 inches. Is this true or not? I've never been able to find anything out and all pics I've seen of the A1 model show it still with the shortened 9 inch barrel.

M203A2 ~ I know it's "designed" for use with the M16A4 rail system, but can someone point out how the attachment method differs from the A1 model? I've seen pics of it attached to the A4 rifle, but the attachment points look to be exactly the same as the earlier model A1.

M203A3 ~ I saw this designation on a military weaponry site a while back. Is there an A3 version in existence? I've searched and searched, but found nothing on it. Is it real or probably just a typo?