There is no polarity on an SMD ceramic cap.
If your wallet can take being emptied (ceramics are a lot more expensive per uF), yes you can replace an electrolytic for the same voltage and value for a MAX232 app.
For the crystal, you SHOULD, but watch your pad sizes.
@solutions: The question have 2 parts.
@alberto110: your answers.
1st is about electrolyte in max232. So answer is yes, because there are existing SMD version of them (still take care about voltage and polarity).
2nd is about capacitors for quartz. They are ceramics and also yes, they existing in SMD version. Bottom line you can use SMD version.