I'd say go for it and learn to read the dots- it's a useful, and transferable skill. If anything it's less likely to cause confusion than learning just from tab, because the dots relate to the actual notes you hear, which helps to develop your ear. That way your head thinks what note you're playing, and your fingers remember where it is!

The nice thing about mandolin compared to the guitar, is that the tuning is completely logical and consistent, which makes it really easy to pick out tunes by ear once you know how to play a scale.