A1 lower is available ish from nodak spud or brownells. With an export permit and import fee. Its almost a $600 lower. If you get the upper from them as well, then it can be on the same permit. But i believe the waitlist at Nodak right now is about 8 months.
Also do your research and see which A1 upper you need for your correct retro build. Some of the early colt 600 series does not have a forward assist. The later XM series, well depends on the variant, should have forward assist amd maybe either a tear drop or round F/A. The correct A1 dust cover is right now the hardest piece to get even if you have all the money in the world. But those are really minor detail.