I'm guessing that the dots are month counters. So July 99?

TREK VRX 300
After taking the fork apart and looking at the 1999 and 2000 Manitou manuals, I've determined this is a 2000 model year fork based on the parts inside. So production got an early start on the next year. Probably typical in many manufacturing areas.

The SX changed considerably from 1999 to 2000. The internals were swapped left and right. Spring & mcus went from from the right leg to the left.
The spring was short with 3 mcus, changed to a long spring with 1 mcu. The dampening went from left to right, from adjustable to not adjustable. I suppose you could adjust the dampening by changing to a more or less viscous shock oil. Overall the fork is well made and easy to work on. It was 'stuck', would only budge a 1/4" or so. Nothing appeared to be buggered inside. Put it back together and it works fine. New oil to the prescribed level. The internals were very clean yet the manual says to change out the oil if it gets dirty. After 20 years, it was still clean. I doubt it anyone had opened up this fork before.

Its back on the bike, a Trek VRX. The rest of the bike need more work. Cane Creek AD-5 shock won't hold air. Grips, brake pads, cables, chain all getting replaced. Parts on order.

Not unusual to have it marked one year before the actual model year. It's the casting date for that specific part of the fork. I've had Marzocchi forks with a three year span of dates on the lowers, crown and arch. Even found different dates on each leg as they are bolted together.