Piston pin noises are higher pitched and make a clink rather than a knock. Piston knock is a hollow clattering sound, much like a diesel makes at idle. Rod bearings will knock quietly for only a short time - they will always degrade quickly into a full failure. If the engine has been doing this for more than a few miles it is the pin or the piston skirt. My vote would be for the piston skirt. The B230 engines of that vintage had a ridiculously short skirt below the pin, and any amount of wear, overheating, or other abuse causes them to make noise. The small end bushings do get pounded out, but mostly on the turbos.
Chances are if you monitor it and it doesn't get worse quickly, it is fairly benign.

My 82 245 has a slight double knock. My research on the board says it's a piston pin noise. Not loud/heavy enough to make me think it's a rod bearing. Noticed it ~year/20k miles ago. Not gotten much worse; it's my daily driver. Takes a hair longer to get to oil pressure than my other 2, but it's got a Fram oil filter.
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`76 242(junk), `83 245DL, 86 245DL, 87 245DL.

That's a sound a worn rod bearing makes. You can usually identify which cylinder is the offender by pulling plug wires 1 at a time (careful, here - best not to do while it's running). When the sound goes away, you've found the bad one.

Assuming you're keeping up with frequent oil changes, what you can try is using a heavier oil - although if you're in the snow belt, that's not prudent until the overnight temps are above freezing. Years ago my beloved Opel Ascona developed a rod knock at 150K miles. I had an oil pressure gauge, so each morning I would bump the starter for a few turns, but not enough to actually start. Once I saw the needle come off the peg, then I would let it start up, and that would minimize the knock. I also went to 20W-50 oil, which helped. I keopt the car another 10K after that, but had to pass it on to an Opel enthusiast since parts were $carce at that point.