  We present an elementary computational scheme for the moduli spaces of
rational pseudo-holomorphic curves in the symplectizations of 3-dimensional
lens spaces, which are equipped with Morse-Bott contact forms induced by the
standard Morse-Bott contact form on $S^3$. As an application, we prove that for
$p$ prime and $1<q,q'<p-1$, if there is a contactomorphism between lens spaces
$L(p,q)$ and $L(p,q')$, where both spaces are equipped with their standard
contact structures, then $q\equiv (q')^{\pm 1}$ in$\mod p$. For the proof we
study the moduli spaces of pair of pants with two non-contractible ends in
detail and establish that the standard almost complex structure that is used is
regular. Then the existence of a contactomorphism enables us to follow a
neck-stretching process, by means of which we compare the homotopy relations
encoded at the non-contractible ends of the pair of pants in the
symplectizations of $L(p,q)$ and $L(p,q')$. Combining our proof with the result
of Honda on the classification of universally tight contact structures on lens
spaces, we provide a purely symplectic/contact topological proof of the
diffeomorphism classification of lens spaces in the class mentioned above
