I’ve dug out my travel diary and I’ve used this route on 4 occasions; Sept 2009, March 2012 and August 2016 & 2022. Since some three years have passed and this route is still active, I’d suggest it would be a reasonable assumption - especially since there aren’t any relevant pathways north to Fort William other than through Dalmuir. The only viable possibilities East-West were a reversal at Stirling*, or Shotts and Carstairs (Airdrie wasn’t opened up then).
*There was an issue at Falkirk High as I recall.