Do you mean the very first load after installation ?
That's correct. After that first load, it will always start with the previously selected board. So the significant issue right now is that the board is not selected when you open a new sketch.
However, I also think the proposal to have the Uno selected by default on that first load after installation is reasonable. Even though it only ever happens once, that first load is the most important because it's a beginner's very first experience.
There is a tricky thing right now though, which I commented on in that proposal:
This is a little bit more tricky than it might seem at first. The reason is that, unlike the classic Arduino IDE, Arduino Pro IDE doesn't come with the Arduino AVR Boards platform of the Uno pre-installed. What happens now is that if you connect or select the Uno from the board menu, the Pro IDE displays a nice notiification that explains Arduino AVR Boards must be installed and offers to do it automatically.
The solution I see is that if an uninstalled board is already selected and you try to compile or upload, the Pro IDE should show that same notification. Currently it just gives you that same painful "Compilation error: Error: 2 UNKNOWN: no FQBN provided" error.
However, that comment was made in the context of the "Arduino Pro IDE" (the issue was transferred over from that repository). With an IDE specifically targeted at professionals, the classic IDE's practice of coming with a the Arduino AVR Boards platform pre-installed didn't make sense. A professional is perfectly capable of installing the platform they need and would not want the hundreds of extra megabytes added to the installation for a platform they might not even use. But for an IDE that is intended to be friendly to beginners, the most important thing is giving them the shortest and most gentle path to blink. In that context, it certainly makes sense to bundle Arduino AVR Boards.