This is nonsense. Why are you folks so hell-bent on proving that the Portuguese & Mughals brought everything to India? Centuries before the Portuguese arrived, the Sanskrit word for Guava was Peruka (पेरुक). The Ayurvedic text Madan Vinod Nighantu Of Madanpal (1374 CE) specifically refers to Peruka: 
"पेरुकं तुवरं प्रोक्तं स्वाद्वम्लं कफकारकम् ।
शुक्रलं वातपित्तघ्नं शीतलं च रसं मतम् ॥"

Meaning: Peruka (Guava) has a combined taste of Tuvara (astringent), Swadu (sweet) and Amla (sour); It aggravates Kapha. Its juice is Sukrala (fertility enhancing), and mitigates Vata and Pitta. The qualities are heat, sharp acting, fluidity etc. and effect is Shitala (Cold).

The Portuguese first set foot in India in 1498, over a hundred years AFTER Nighantu was composed.

The same Nighantu also reveals that Pears were called amritphal (अमृतफल) in Sanskrit. It is Mughals who didn't know squat about Indian fruits and called pears amrud. So your theory about guava being a “new world” crop which assumed its name in association with the closest available familiar produce is incorrect. Just as the theory that people of Maharashtra & Goa call it Peru in memory of the Portuguese is also contradicted by the fact that guava is called  "Peyara" in Bengali. 

Guava or Peruka is an indigenous Indian fruit which pre dates the Portuguese.