First scan p. is of a fol. 6 (marginal keyletters KA and CHA), with more fol. nos. going as high as 60 and 65. A word search of a passage found in scan p. 73.6) tells me this is Tôh. no. 4231, Rigs pa'i thigs pa'i rgya cher 'grel ba. (Dan Martin's Hurried Notes)