Hi,
Using permanent 301 or temporary 302 or 307 matters a lot.
Say, you are using an id# in masked url and for moment id#1 is redirecting to abccasino.com and after couple of days you redirect id#1 to 123casino.com. in this case you need to use temporary redirect.
Bots uses the same logic which we guys use. If the masked url is for permanent redirect thn use 301 else use 302 or 307. Things will go upside down if you are using 301 and keep on changing the redirect url and in contrast vice-versa will not make any harm.