I still don't understand. are you telling us that you installed a new engine into your car, and didn't even check or change the oil? and then left it for 2 months? What is the wrecker had drained the oil before you fitted it? or what if that engine has been sitting around with the same oil in it for 2 years?
My advice is forget wondering about why someone blocked up the dipstick hole. it's completely irrelevant. Get a dipstick tube, and a dipstick, put it in, then for gods sake change the oil!