It is not the end of the world for the camera, but you will have to use it in stop-down (non-metered) mode, sans TTL and meter with a handheld spot/multispot/duplex/incident meter instead (your Sekonic 308, which is a valuable additional skill anyhow with the TTL meter only going as far as 1 second!).
It is too late for you at the moment, but this procedure must be followed when removing/re-mounting the prism to protect the chain:
https://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/372838-...ter-prism.html
The lens mount uses shims and these must be replaced in the exact same order they were removed. The mount must then be calibrated for accuracy (this requires a bench device to do correctly). New chains have long since disappeared into history; jewellery/beading wire ("tigertail") is the wire (available at most craft shops) most often used now to repair the chain: it is very flexible and very strong (much stronger than the OEM chain), with ready availability of crimps and tools to effectively do the job (and the job requires accuracy and dexterity to feed the chain around the mount and hook it up to the aperture coupling). Oh, and it comes in myriad colours, too!!
---------- Post added 15th Feb 2020 at 11:04 AM ----------
Originally posted by Kmier Sorry to jump in with a question, but I thought that by the time the 67 bodies came out, the sequence of removal / install of the finder was no longer an issue wrt the chain?
If you are referring to the Pentax 67II camera, that model does not have a meter coupling chain.
This irksome problem only occurs with the earliest and latest Pentax 6x7 and Pentax 67 cameras respectively, not the 67II.