The information in this answer is general information and is not intended as legal advice, nor do I intend to create an attorney-client relationship with any reader by answering this question or otherwise contributing as a member of Trulia.com.
The Dec.07 date is irrelevant. Correction of any outstanding violations becomes the liability of the current owner regardless of when they first occurred. If the violations are older they may have already been corrected over time. In such a case you would still be liable for showing that those corrections were done with permits, by licensed contractors and Code compliant. Depending on the type and severity of the violations, the City may or may not seek to enforce the rules.
If the Seller/Realtor is giving the Dec.07 date to you (the buyer) as a cut-off date, then I would suggest have your attorney write up something that puts the Seller on the hook for any costs incurred for anything prior to that date. You should be aware though even with such an agreement, getting money later from the Seller is highly unlikely and would probably involve a lawsuit. Typically it is a waste of time and energy. Consult your attorney.
There is no good, sure fire way of looking up outstanding Code violations online. One can check the CCRD for any court cases or liens from past cases as a start. Currently, the only thing that pops up for the address is a water lien. You can also check the City's website for info.
The best way to verify any outstanding violation notices is to go to City hall and do a FOIA request. This will get you whatever is on the system currently for past or present notices. However, if you suspect that the City has been out to the building recently, a violation notice may not be on the system yet. There can be a significant lag time between inspection and getting a violation notice. Weeks to many months is very common.
If you want to buy this property; and if you suspect the City has been out to the property; my suggestion would be that you factor proper Code violation compliance work and attorney's fees into your budget.
I realize this sounds self-serving but I would recommend getting a home inspection. An inspection can help answer what some of the potential City issues might be.
It appears that the original front porch was enclosed in recent years. Permits, proper joist size for occupancy load, original wall opening headers and sufficient heating would all be issues to be concerned about. If the interior has also been rehabbed, that would be another concern.
Costs could be minimal or $10K+ easy.