Some HOA's are very relaxed about their rules and some are very strict with enforcing things such as parking RV's, items in the front of the house such as trash cans & basketball hoops.
If you are really concerned and want information before you put an offer on the home, ask your Realtor to get the information from escrow so that you can review it before you submit your offer.
I see you are located in San Diego- fortunately most San Diego (SANDICOR) MLS listings have HOA contact info on the listing. This is very helpful and should also be available in the Riverside county MLS (although it is not at this time).
If the home is an REO you can also try searching title reports for any HOA liens recorded. Sometimes you can find out which management company runs the HOA via title records as it may be on the preliminary title report. Your agent should be able to assist you with these searches and if all else fails you can talk to one of the neighbors to get contact info for the HOA.
Good luck and I hope this helps.