had or no had

[hal24]

I know you need to use had to tell that something did happen before something else.. But in this case I cannot tell if I need had:

I am wondering if you had received the letter
I am wondering if you received the letter already.

Different question: I want to say there are more than one type of actor..

is there any difference between these two sentences?

types of actors
type of actors

Thank you in advance for your your answers and help.

[fighting spirit]

I am wondering if you had received the letter
I am wondering if you received the letter already.

Neither is correct. In this case, you need the following construction:

I am wondering if you HAVE received...

As far as the second part of your post is concerned, if you say a type of actors, it refers to ONE type of actors. If you say typeS of actors you refer to many, or more than one type of actors. That is, in your case, you should say TYPES OF ACTORS.

Oh, this sounds pretty but I'm in a hurry

[5jj]

Neither is correct.

Actually, both are possible in the right context:

I am wondering if you had received the letter (when you left home this morning)
I am wondering if you received the letter already. Possible in some AmE dialects.

Also ;

I am wondering if you received the letter. Fine.
I am wondering if you have received the letter. Also fine.

[5jj]

If you say typeS of actors you refer to many, or more than one type of actors. That is, in your case, you should say TYPES OF ACTORS.

That is correct in other situations, but as you show in the words I have underlined, 'more than one' is used with singular nouns and verbs. The natural choice is therefore:

There is more than one type of actor.

[poorboy_9]

I don't mean to nit-pick. but.......
Doesn't the phrase you underlined "more than one type" naturally refer to a "plural" context, thereby eliciting the "plural" form of the noun = types?
B.

[fighting spirit]

I completely forgot that he refered to the following sentence:

I want to say there are more than one type of actor..

I'm really sorry

[5jj]

I don't mean to nit-pick. but.......
Doesn't the phrase you underlined "more than one type" naturally refer to a "plural" context, thereby eliciting the "plural" form of the noun = types?
B.

No.