Fabricated Arms who is milling my standard slide P365 for a 407K is awaiting a confirmation from China of the EXACT specs. Apparently, the posts holes on the 407K & 507K are not as deep so the posts on the mounts will have to be shorter. Or something like that. Best suggestion, wait until you have the new micro Holosun in hand and mill to fit.
I've had a 407K on order with Optics Planet for two months. Ordered the very first day they posted availability just after intro at Shot Show. If you read the fine print, there's now a new disclaimer due to COVID it could be a couple more months, at least. But I think it will be worth the wait.
Thanks for the discount code though. I'm going to contact CS and see if they'll apply to my backorder.