Not sure the video is up yet, but this woman (Ellen Cherry) played a nice Guild I am too much of a newbie to recognize.
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http://www.mpt.org/programs/artworks-season7/728/
Back braces indicate it's flatback so must be an F50
R: rosewood B/S.
Ruling out JF-55 version of those because those got abalone rosettes when they moved to black 'guards ca '94, but early ones were tortoise and this one's black; although we know anything's possible with Guild.
So pre-87 (when the "JF" model numbers came in) or post '01 F50R, suspect pre-'87 build due to p/g color shape and color; tortoise looked to be the standard 'guard color when the model number was reinstated in Corona in '02 and thereafter.
Something about pickguard shape makes me lean towards a '70's F50R.
There was a slightly smaller and much rarer model that used that type of neck, the GF-55, but all the pics I can find of those show tortoise 'guards.