Aradhana in Bengali was a dubbed version of the Hindi film, it wasn't re-shot, I think I may have a copy of it on VHS somewhere. Shakti Samanta started making dual versions of his films much later, with Amanush, Anand Ashram and later, Barsaat Ki Ek Raat (Anusandhan in Bengali), and Aar Paar (Anyay Abhichar in Bengali).
With regards to the songs, Kishore Kumar sang the Bengali version of Gunguna Rahe Hain Bhawre, but Rahul Dev Burman sang the Bengali version of Baghon Mein Bahar Hai, both of which were sung by Rafi in the Hindi version.
There has been a '4K' version of Aradhana uploaded - unfortunately this is cropped though:
https://www.youtube.com/watch?v=hr-BOE45uE0