new addition to the family : 1992 244 40 miles : probably has only been driven 'around town', engine oil changed 1000 miles ago, (just drove 300 miles at 65-70 mph) two days later checked the oil - seemed very dark, checked the oil cap and there seemed to be a bit of white oily froth (water and oil?), the coolant level has not changed - it runs beautifully. I just dropped the oil out and replaced it again to monitor the oil color. I do not have receipts or verbal communication with the one previous owner so it makes me a bit nervous?

would the engine if never driven on the highway build up some 'guck' that would dirty the oil for the first few times she gets rolling on the highway ?

any advice or experience is appreciated