lmorovan,
The context of the account does not support your inference and neither does a study of the Greek word interpreted in this version as "vision". If you require further evidence that this was not a sleep vision given to 3 disciples you only need to look to the account in Luke.
Luke 9:28-32
28 Some eight days after these sayings, He took along Peter and John and James, and went up on the mountain to pray.
29 And while He was praying, the appearance of His face became different, and His clothing became white and gleaming.
30 And behold, two men were talking with Him; and they were Moses and Elijah,
31 who, appearing in glory, were speaking of His departure which He was about to accomplish at Jerusalem.
32 Now Peter and his companions had been overcome with sleep; but when they were fully awake, they saw His glory and the two men standing with Him.