I have noticed a couple of times when accelerating hard in first or second I feel the clutch may be slipping.Usually the bike is laid over a little because I was turning right or left onto another road from a stop. But if I try to make it slip by rolling the throttle hard while doing 40-50 in third, fourth, and fifth gear I get no slippage. Bike has 94K.

It could be slipping from wear and still not slipping under a higher speed load. The test is as you have done. 4th gear and roll on full throttle at about 40 and if the RPM increases faster than the bike, it is slipping.

Sounds like you still may have a few miles left in it but something to keep an eye on. If you area t the beginning of one of the 3 catastrophic failures ( O-ring, Slave Cylinder, rear main seal) I would think you could recreate it at 40 with full throttle but then again.....

You might drill the weep home in the bottom of the bell housing as an early warning of seal failure but it just sounds like something you need to watch and see if it worsens. Keep an eye on your clutch reservoir level. If it is dropping, you may have a leak there and the only place for it to go is down to the clutch.

A clutch can surly be worn out in 94K but it could also go much further baring oil contamination depending on the user.

Usually slippage if first noted in higher gears as you imply. Do you have an oil stain on the right side between engine and transmission cases? If so you probably have the famous O-ring failure. The 19x4mm one that seals the engine case to flywheel. A rather massive job. On the other hand just about 100,000 miles could be the end of your clutch anyway. Either case, while in there change that O-ring. Here is some reading:
GregRS's journey into seal territory - I-BMW.com

Very unlikely to have a clutch slip in first and second and not the higher gears as torque demand is less in the low gears. Are you sure you aren't feeling tire squirm or slip. I felt this often with the K1600 I rode in Europe, but not so much with the wimpier 1200.

Checking for oil as already mentioned is a good idea.

Thanks to all respondents. No sign of any leakage. I will check fluid level. I do think it might be wheel spin.

yes you can get clutch slip in 1st and 2nd if,, you are in stop go conditions its hot outside and riding the clutch to take off, the clutch gets in an overheat condition. Make sure the clutch is fully engaged before you accelerate hard.
I learn't this when I first got my beemer after trading my honda many years ago