Stem Leak on Older Nibco Ball Valve

[wraujr]

I have two NIBCO ball valves on the incoming water supply.
One is before the meter, one is after the meter.
The one before the meter, was replaced three years ago when main line replaced and it has a packing nut.
The one after the meter is from original build in 1993. It does not appear to have a packing nut.

In the past couple weeks the older valve has been used a couple times for toilet repair and water heater replacement.
Each time a drop of water appears at the threads where handle nut is. First time, it appeared once. Second time a little more.
Hoping it will go away on its own....
Obviously water is coming from shaft/stem. Prior to this valve had been turned almost never for 18 years.

I know all about packing nuts etc., the questions here is to the old, experienced plumbers who may have worked
with the older NIBCO.
Can tightening the handle nut on a older NIBCO (without packing nut) help with a stem leak??

[LLigetfa]

A single drop of water is nothing to fret over. Probably just from condensation. If the stem were leaking it would not likely present at the threads of the handle fixing nut but rather under the handle where the stem exits the body.

I say leave well enough alone.

[hj]

If it does not have a packing nut, then the seal is probably with an "O" ring, and if so, it does not depend on anything compressing it, so the answer is "probably not".

[wraujr]

Update:
(a) Definitely not condensation.
(b) Part is NIBCO 580, and mechanical diagram shows it using a "Packing Gland", not a packing nut.
(c) Definitely no packing nut, so ended up tightening handle nut a "smidge" and droplet went away.
(d) Found this today on NIBCO website under "Operation and Maintenance Manuals".

"Routine maintenance consists of tightening the packing to compensate for wear.
The handle nut also provides the packing preload on the 580 ball valve. When leakage
occurs, the handle nut should be tightened in 1/8 to 1/4 turn increments just enough to stop leakage."

Well, there ya go... not all ball valves have a packing nut and some of these you do tighten the handle nut...
Sheesh.. nothing is simple or consistent...