If you really only intended to send a couple of these, I can't see it being a big problem. It's not as if you will be doing a bulk mailing to thousands of names picked at random.
But, to be on the safe side, I suggest you observe the following points:
Keep the whole message short.
Personalise it - not just by manually adding a salutation, but by making it clear in some way that the message is intended specifically for the person or firm to whom it is addressed.
Most important: Include the following text, or something similar:
<font color='#0000cd'>If this offer is of no interest to you, please ignore this message. I will not trouble you again.</font>
I think the above form of words is much more useful than an unsubscribe message (which, in any case, would be inappropriate, because it would suggest that the recipient is "subscribed" to something, which is the opposite of what you are trying to convey).
Now, having said all that, keep in mind that practices and customs vary from country to country and from place to place. But, in most cases, if you follow the above points, it's unlikely you'll have any problems.