The standard Aulos says “Double keys for low C and C#”, so I think it’s good.
The two “serious contenders” in the plastic tenor world are the Aulos Symphony and the Yamaha, and both have low C# so that is not really an issue. I think it’s worth remembering that, until recently, most recorders were (more or less) copies of surviving baroque and pre-baroque instruments (Moeck Rottenburgh, Mollenhauer Denner, etc), and almost all of those did not have low C#. Probably for that reason, the note virtually never appears in pre-twentieth century music. Even if it does, you can substitute low E in most cases.
The total reach on the plastic Yamaha and the Aulos Robin are almost identical – I have both in front of me now. The left hand hole spacing is virtually identical. The holes are a bit closer together on the Robin for the right hand, but there is no key so you have to directly finger all of them; the distance from hole 4 to hole 7 (Robin) or keys (Yamaha) is also pretty much the same. I think the choice boils down to whether you prefer to use the keys or not, and which sound you like the most. The Yamaha is a good quality instrument but I personally find it too bright. An advantage of not having keys is that there is nothing to go wrong. Not having keys is certainly not unconventional, and neither is having a single key and no low C#. It really does come down to whichever you like the most.