for stock speeds its really hot, but not dangerous, when I had a bad fan on my 1200 it ran at 64C at times and still stayed perfectly stable. I wouldn't recommend a Stock heatsink for overclocking, getting a good heatsink is a MUST! when you have good cooling one of the headaches that overclocking gives is gone, so u have one less things to worry about. Also consider tiding up all the cables inside the case and put at least 1 intake (front bottom) and 1 exhaust fan rear top to get some air flow in the case.
Try to experiment, get Prime95 (stress proggy) and let it run when the case is closed, record the temps and remove the case cover and let it run again. now if your temps with the case off are lower than they're with the case on, you need more air flow, in my "Secondary rig" my temps are actually lower with the panel on due to a good air flow. the main PC will be getting its mod soon enough to get some airflow as well.
Get a good heatsink such as Thermalright AX-7 or SK-7 or SLK-800 (performance goes from worst to best, not MUCH of a difference tho) coupled with a high CFM fan such as Delta 68/80CFM or a Sunon/Vantec Tornado 84CFM fan, will give you very good cooling