Even some brand new cases have had the lifter bores destroyed in less the 5000 miles. I would consider a few things first:
1. How many miles are on the case? If the mileage is low, have the bores re-sleeved with brass. Check through everything to make sure your good to go.
2. If the case has high mileage, trash it and purchase a new genuine VW case.
Many older cases need to be line bored. However, if it's not done perfectly you will never get correct oil pressure numbers. The motor WILL run hotter and wear out much quicker.
Time is money, my opinion is do it right the first time