I've heard that too, and it seems pretty likely to me given how proto-Arabic [g] fronted to [ɟ] and thence to various other sounds post-Classical Arabic (like your "satemization" example), presumably to further differentiate it from [ɢ] while [k] had no such contrast present and hence remained unaffected. That said, it definitely could have been a tenuis stop while /t k/ were aspirated. It's hard to say, especially since voicing contrasts with stops seem to be hard for languages to maintain at the uvular POA. (Plenty of languages have /q/, and a smaller but not that small number have /ɢ/, but surprisingly few have both.)vokzhen wrote:I've also heard Classical Arabic actually had [ɢ], in which case a reflex of /g/ might just be fronting, but I'm not sure I buy that (afaik that's based on /q/ being classified by Classical Arabic grammarians along with /b d/ rather than /t k/, but a voiceless, unaspirated could have been thrown in with either).
FWIW, I've also seen resources on Arabic claim that all emphatics were voiced in Classical Arabic, giving [dˤ] for modern [tˤ] and [zˤ] for modern [sˤ].