Some lenco platters have balancing marks underneath.
I found a considerable sonic improvement from my lenco 99 when I smothered platter with blue tac asevenly as I could and wound lead solder round it also evenly. Then made sure the platter was exactly level and fitted Len Edwards bearing machined as though it were a swiss watch.
The 301 I left alone plonked it in a slate deck and it completely traced the 99 wiped the floorwith it.