Yes. In the products csv upload we'll just need the ProductId (which must match the products you're updating) and the column to update. Eg updating the lead time we'll just need a csv file of 2 columns ProductId, LeadTime.
You can also upload as many columns as you want (eg: updating the LeadTime, MinimumOrderQuantity, and StockOnHand) will require a csv file with columns ProductId,LeadTime,MinimumOrderQuantity,StockOnHand.
Any existing data related to columns not included in the file will remain the same.
Note: Updating a column with all rows blank will clear out all that data. So only do this if you deliberately want to clear that data.