Hello,
Although no such tests have been completed with Teltonika devices, it is unlikely that RUT240 or 955, would support that many simultaneous users and provide reliable connectivity. Wireless 802.11n standard, supported by the discussed devices, has an upper limit of 2007 associated clients, but there are limits set by available bandwidth, WAN source, CPU capacity, equipment distance from the access point.
To sum up, you could test it, though, in practice, significantly worse performance should be expected.
Bets regards,
Žygimantas