Yes, I think there must be many similar letters between Tha alphabets and Javanese, since they derived from the same language and culture. Javanese were once strong buddhist too in the past.
Btw... the more older Javanese language that is partly used in a traditional opera show or puppet show has actually also different sets of alphabet, I just never learnt that alphabet. However from a short look they have more similarity to Thai alphabet set.

That's some example of traditional alphabet from different tribes in Indonesia. There are still some more, since Indonesia has hundreds of tribes. This picture was uploaded in Facebook by Komunitas Aksara Sunda Bogor.