(for pure speculation and reflection)
I'm no expert, but I'll confirm it. You see it a lot in Zhang-zhung titles to Bon sutras, so it absolutely must be genuine! The language of that particular region in the heart of Zhang-zhung was regarded as the literary standard, hence the 'letters' (yi-ge) meaning... Or at least I'm accepting this in lieu of other reasonable explanations that might be offered by an expert in speculative etymology. Maybe it's a "little gug," whatever a gug might be. ("gug ge" and "bu ge" are two manuscript variants) Maybe you could look up this obscure publication in an obscure German bibliothek, since it may conceivably be the answer to all doubts:Studien zur Sprachwissenschaft der Tibeter. Sitzungsberichte der philos.-philol. hist. Classe der bayerl. Akad. d. Wiss., München (1898), pp. 590-591. It's on the title in Zhangzhung: Dal ling a he gu ge bya.
Dear D, thanks a lot from Chengdu. I feel confirmed. And “little gug” is a “little curve/stroke/bent” or rather “little twists and turns”? This is one of wildest speculation. D.