Sizing for a tt bike

Height is a really poor indicator of fit... You can take two people of exactly the same height and it's entirely possible (even probably) that one will fit and the other won't. It's not only body measurements (lower body/upper body, arms, etc.), but also flexibility, core strength, athletic background, distances/terrain racing/training, current/prior injuries/issues, etc. etc. etc. that all influence the fit.

I understand what you are trying to do, getting a used bike at an attractive price, but there's simply no way to say for sure if it will fit or not. Height might help you avoid a complete disaster, i.e. at least you can make the bike work for you (although you might have to do quite a few compromises to get there, hence making you slower than you should be), but it's not a guarantee.