Short answer is yes. I have a 10.3.1 and 2 different 10.5 LM's serving various needs so you can install the LM software as many places as you need.
Regarding a pre-auth I am not sure what this means? With ESRI either it's authorized or its not. Your only limitation here will be the number of licenses you have paid for.
If you have an unlimited ELA then it's simple and you grab whatever you need via myESRI site as a .prv (500 advanced desktop, etc.) and load the new LM. If not then it gets more interesting and maybe someone with recent experience can speak to this as I last did this 3 years ago but this is essentially the same workflow if you have an ELA but have limited licensing for extensions such as Data Interoperability.
Under individual license scheme (non-ELA) then you had to go into your existing LM, return the licenses to ESRI, wait 24+ hours for myESRI to update and process the licenses have been returned, pull down the licenses for new LM, load new LM. We schedule and plan rollouts ahead based around this due to some limited licenses for various extensions. Our workflow is letting people know that end of business on a Thursday users of the limited licenses will no longer have access to the tools until the following Monday. That means a single Friday where they do something else and ensures a working business day on ESRI end. Over the weekend we push a registry key update to all systems to divert to the new LM server. I come up in early (before most/all users) and pull limited licenses back down then load the new LM.
Have occasionally had an issue with licenses not being available again but that has quickly been resolved after a short phone call to ESRI and hasn't impacted work past noon of that following Monday. It may be possible to "pre-load" your new LM with limited licenses but that's certainly going to take a call to ESRI.
