Sounds like it. I can usually see the same thing at the foot of the bed and the motor is definitely slower. There is also a rubber seal on the top of the slide that "flips" when sliding in and out. I have noticed that until this flips it is slower as well. Once it does "flip" it speeds up.
Doesn't sound like you have a problem at all.
Jack of all trades - Master of none
2012 F350 CC DRW - 6.7L PSD
2014 Sabre 36QBOK