You can make an offer for any amount of money on any property at any time. That being said, when you make an offer for this condo, you should make it a realistic one so the Seller will take your offer seriously. You might get a counter offer from him/her until you come to a price on which you both can agree.
If you go to my "Links" on my website or go to http://www.sfgov.org, you can learn the requirements for ownership of a BMR unit. Be sure you understand them both for purchase and for re-sale for there are restrictions on the unit both for buying and selling.
If you do not have a Realtor, interview a couple of us for you do need your own representation. Do not go with the Listing Agent for he/she has a fiduciary responsibility to the Seller and your Realtor has one just for you. If you have a Realtor, talk this over and make your offer. The time to buy is now while prices and rates are low!