Is 1:00 AM a reasonable time for police to conduct a search of the room of a registered guest who happens to be on probation?
Additionally they lied to gain entry by staying out of the view of the peep hole in the door and identifying themselves as "front desk". Once the door was opened they barged in without permission nor consent to search.
There are some unknown factors here that make a difference in assessing whether police actions in this situation were either reasonable or legal. The first factor is why the police showed up at that particular hotel room at 1 AM? It is most likely they were responding to a complaint or a tip, either by the manager of the hotel or someone renting another of the rooms there. When they receive a complaint specific to anything illegal in a location, a search is not unreasonable, nor would the time be.
Depending on the state the incident took place in, courts have often ruled that a hotel room is not the private property of the person renting it, so the only consent they would need to obtain would be the manager's or the owner's. Lastly, it depends on the terms of your probation as to whether or not random and unannounced searches of your property or person can take place.
Just based on what you have stated here, however, you would have a difficult time proving police malfeasance. Legally they are required to identify themselves, but it is difficult to prove when they do not, particularly if the person making the complaint has prior convictions.
From West's Encyclopedia of Law:
Statutes may also identify conditions of probation. These are actions that a probationer must do or refrain from doing during probation. Though conditions may be spelled out in statutes, a sentencing judge retains wide discretion to fashion conditions according to the best interests of both the public and the defendant. In most states a probationer must not possess a firearm, commit another offense, or possess illegal drugs during the probation period. Probationers must also report regularly to a probation officer.
A judge may place additional conditions on a probationer. For example, if a defendant pleads guilty to assault, the court may order him to stay a specified distance away from the victim of the assault. In a conviction for a small amount of marijuana a judge may order the defendant to complete treatment for drug use. If a probationer violates any condition of probation, the court may order additional conditions or impose a prison sentence that does not exceed the maximum term of imprisonment that could have been imposed for the crime.
Look you have to understand what is happening in the world. Sometimes authorities like police may get wrong information. You have all rights to be disappointed but may be the police has information about a criminal. Do you believe if they would announce police then situation would be easier? They know their job. As a citizen we should assist them to build a better world.