Yes, it is correct.
In this quote, “devoir” is used as a modal verb, as would the verbs “pouvoir/can”, “sembler/seems” and “paraître/appear” (which could also be used in this sentence).
You can find more informations on Wikipédia: Les auxiliaires de modalité épistémique : sembler, paraître, pouvoir, devoir.
They are used to add some degree of uncertainty.
If you use “ça doit se trouver là bas” you are pretty sure it is, with “ça peut se trouver là bas” you are pretty sure it can be, and with “ça doit pouvoir se trouver là bas” you just think it makes sense and it should be there, but you’re not sure of anything.