Probably the last questions before the upgrade are below.

Google states in its reCaptcha installation instructions "Paste this snippet at the end of the <form> where you want the reCAPTCHA widget to appear:

<div class="g-recaptcha" data-sitekey="XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"></div>

The data-sitekey is the public key generated by Google for reCaptcha v.2.

Question1.
Do I need to paste the public key as stated by Google or the public key has already been integrated in the
/includes/functions/extra_functions/recaptchalib.php ?

Question 2.
If I need to paste the public key, where do I find the "form"? Is this the php file that defines "contact us" page?
Also, there are three pages on which reCaptcha will appear contact_us_default, create_account, and product_reviews. I assume that I will need to paste the public key in all of them. Please confirm.

Thank you very much.