The Certificate of Sale does not require registration. But, if it is presented for registration, it has to be duly stamped under Article 23 of the Indian Stamp Act, 1899.

2) 

AIR 2013 MAD 73 [Dr.Meera Thinakaran Vs. State of Tamil Nadu & two others], wherein it has been held as follows:-

20.Now, coming to the next contention of the learned counsel that the Recovery Officer appointed under the Recovery of Debts due to Banks and Financial Institutions Act cannot be construed as a Revenue Officer as contemplated in Article 18 of the Indian Stamps Act needs to be considered. A similar question arose before a Division Bench of this Court as to whether the Sale Certificate issued by the Recovery Officer under the SARFAESI Act will fall within the ambit of Article 18of the Indian Stamps Act. The Division Bench in K.Chidambara Manickam Vs. Shakeena and Ors, reported in AIR 2008 Madras 108 has clearly held that such a Sale Certificate issued by the Recovery Officer under SARFAESI Act would squarely fall within the ambit of Article 18 of the Indian Stamps Act. In view of the said law laid down by the Division Bench, the argument of the learned Advocate General deserves only to be rejected. Thus, I hold that the Recovery Officer under Recovery of Debts due to Banks and Financial Institutions Act will fall within the meaning of a Revenue Officer as enumerated under Article 18 of the Indian Stamp Act. Thus, a Certificate of Sale issued by him will squarely fall within the said provision..

It is your choice to register as there is an exemption in registration Act. It's not mandatory to do so. But stamp duty is mandatory to be paid.

There is no concession in the stamp duty for registration of property sold by the bank under Sarfaesi Act you can get your property registered as soon as possible when you got the position of the property from the bank after payment of your consideration amount

Documents that have to be mandatorily registered, should be presented within four months from the date of their execution. 

There is no prescribed time limit generally. 

However, you must once confirm the same with one local lawyer 

Sir there is no concession on stamp duty , you can present sale certificate properly stamped with the registrar and the registrar shall register same. Though it is not mandatory to register a sale Certificate. 

The time limit is four months.

No concession is available for the stamp duty in this circumstances. 

Dear Client,

Dear Sir,

A sale certificate is generally issued by the Banks when the property is sold by the bank in public auction to recover the outstanding loan amount under the SARFAESI Act. ... The purchaser needs to pay the stamp duty on the sale certificate and get the same registered in the sub registrar office to make it legally valid.