I have some plans on buying a cupel of extra sheaths for my and my fathers RMKs sins we both will use them a lot so the new ones will be wear and tare and the original safe and sound.
For example i know it's possible to order a model c for the model 16 and a model a for the 25-5 but how can you mix theme?
Can i order a model c for the model 1-7?

All of you take care

I don't know of all of the possible combinations BUT I believe you have to return the knife or knives back to Randall so when the new sheath is made they fit it to your knife before they set the keeper strap snap. Given your location it'll involve some extra expense!
I don't know if they'll build one without the knife.
I'm sure the Captain or someone else more knowledgeable will chime in on this question.

Seeing as how you are using this sheath for a "user" and not trying to "flip it on Ebay" you can get Greg at Sullivan's to supply sheaths "without" Randall logos, trademarks, snaps, etc. (Fill in the blanks). They will be cut exactly the same way as Randall sheaths, but will be stamped with the Sullivan;s sheath stamp "only" and silver, brass or black snaps. This way no rules are broken and the cutter/clicker die is used, saving that "custom-cut" problem. Greg often has these type of sheaths in stock or in the works. Email me the exact models and I can possibly help you with these type of sheaths.
Yes: A Model #1-7" can be ordered with (and therefore it is made and available) a "C" style sheath. Same sheath as the #16-7", Special Fighter,...available in tan, black or waxed. Hope this helps.
Best, Capt. Chris
PS: If you want a Randall sheath stamp ans snaps your knife is required for final fitting. The sheath will receive the additional "R" stamp, indicating a "replacement" sheath...CCS
PPS: Don't forget about the availability of the new "HI-RIDE" sheaths from Greg...CCS

The Mod. C sheath is available for your Mod 1 and for the Mod. 16 but not for the Mod. 25-5.
Send me a personal E-mail at my shop address and I'll give you more details,
sullivans@tampabay.rr.com
Best, Greg.