Hi pyram,

I am a local. Most probably the name must be written in native Marathi  language. Hence two different versions are possible. 
From his name  it appears that Mr Agarwal is from other north state UP, Bihar etc where state language is Hindi which is closer to Marathi so Narain looks like a Hindi pronouncation. I suppose Narayan is correct. Please do consult another expert from Maharashtra if possible.
(This is not a company)

Thanks and Regards,
Milind   