From independent sources, I'd go with the India.com version: India never received any such offer.
The UN actually existed during WW2. This is what the group of countries allied against the Axis powers called themselves. The Security Council was the group of countries that were actually the major allies supplying large numbers of troops in the fight, and thus needed to periodically get together to coordinate grand strategic war plans. If you read Churchill's history of WWII, he mentioned that China was included in these meetings because they were actively fighting Japan (in a way, those two were the first belligerents of the war) and Roosevelt insisted they be included. I get the impression Churchill didn't share Roosevelt's view of the value of Chinese involvement. However, their relative feelings about France were essentially mirror images of this, so both France and China were put on as sort of a compromise.
This explains why votes from permanent members of the Security Council of the UN require unanimity. During the war, it would have been actively harmful to the UN alliance (which had to be maintained if they hoped to survive) for one group of members to engage in a major action the rest were dead set against.
After the war, some of these countries became enemies with each other, so there was no way they'd agree to change the rules in a way that significantly lessened their own power. This is why this little club has never really changed, and the "non-permanent" members do not get vetoes. This is also why I highly doubt there ever was (or ever will be) any real offer to add India, or anybody else.
In short, permanent membership is not a statement of your country's value or size or anything. At this point its just a historical accident.