I have just installed a viewfinder in a P67 under the watchful eyes of a 'official' repair person. Quite simple if you know the tricks anyone interested may e-mail me directly.
Are you referring to installation of a viewfinder of focusing screen? The Pentax 67 has several easitly-interchangable viewfinders, but changing the focusing screen must be done by a Pentax technician. <p> Joel Collins | jwc3@mindspring.com | http://www.mindspring.com/~jwc3
Having it installed by Pentex is safe but time consuming. I have done it myself with no problems. Email me for instructions