Not sure I would sell as a unit. The 407k is not as well known as the 507k, and some may not prefer the 6 MOA dot.
The slide comes with the barrel, yes? An idea might be to go to Sig's web site and see if there are any new, equivalent kits they offer. Use the retail equivalent as a guide, and price what you want out of it. I have a P365X and sometimes ponder getting a slide/barrel I can experiment with in the XL configuration, so I would thing there would be a market for this.
I'm not qualified to offer a number, but just some ideas to consider.
The slide comes with the barrel, yes? An idea might be to go to Sig's web site and see if there are any new, equivalent kits they offer. Use the retail equivalent as a guide, and price what you want out of it. I have a P365X and sometimes ponder getting a slide/barrel I can experiment with in the XL configuration, so I would thing there would be a market for this.
I'm not qualified to offer a number, but just some ideas to consider.