I doubt as the Freising monuscripts from the turn of the 1st milenium are already written in a form of early Slovenian and not OCS. Also, they are written in Carolingian minuscula, a latin script and not Glagolitic. I believe the latter had no great role in the Slovene lands as didn't OCS. The messes were held in latin and the preaches were in Slovene. Gothic and later Bohorič script were used.