GBS is hallmarked by ascending weakness and loss of reflexes simplistically put, with a mean Nadir of 9 days.Tendon reflex loss occurs early in most (70%) but not all patients, progressive reduction during 1st week with the clinical pattern of distribution were in ankles most frequently lost; biceps...

Absolutely. This observation is more common in axonal variants of GBS like AMAN with GM1 antibodies. With classic AIDP reflexes are usually lost. 

The reflex status is variable, should be checked daily while in ICU.