Pete,

I have not developed 16mm Orwo in Rodinal. But have run 16mm UN54 through Xtol, D76, Caffenol and D23 without issue as B&W neg film. For Xtol and D76 I use 7mins at 20C, in D23 I use 12mins at 22C and in caffenol I use 12mins at 24C. Why is my temperature scale increasing you ask? Well it is because the darkroom was getting warmer as I moved into summer from winter and that was the ambient temp in there as i was working my way through my developers.

The Orwo makes a good B&W reversal 16m cine film by the way, but I use different developers for that process.

As earlier postings indicate, grab a small strip of film and test to be sure.