If premie was born 5 weeks early and is in 50th percentile@3 months (real age)and in 75th percentile for 2months (adjusted age) is this good? caught up?

Depends: Growth charts have been developed for premature infants, so the answer depends on whether the percentiles you listed are based on a premature growth chart, a regular growth chart with the plot adjusted for gestational age etc. In general though, we allow a child up to 2 years of age to "catch up". The child is considered "caught up" when they plot between the 3-97% on a standard growth chart.

Yes: It sounds like he is doing fantastic! keep up the good job!