Whether partnership firm to follow as 7 ?

Yes definitely. AS 7 is mandatory as far as all entities are concerned. When discharging attest functions members must qualify non adherence to mandatory accounting standards. This is esp true for tax audit cases. It would be more value addition to the client if you convince them to follow AS 7 and guide them in the process rather than merely qualify the report. even if you qualify, it may be very difficult for you to quantify the effect of the qualification