I am sure that there was a Jewelry store on 5th Ave, Manhattan, called "Peikin Jewelers" sometime between 1940-1970? Currently there is a store called 'PEIKIN EMPIRE" in Florida...perhaps the next generation or two following the "Peikin Jewelers" in NYC, who I heard were from the "Atlantic City, NJ" branch of Peikins.
As to the spelling...the first "Peikin" to arrive at Ellis Island was named Aaron Paikin, married to Sore, and they arrived around 1893. There are Paikins who live in Canada....in fact, we're most likely all related. I don't know of any Pikens, but I will look into it. You might look at
www.kornspan.com under one of the links, and you will find many Peikins. I hope that this message gets to you. If you wish to speak, I live in metro Washington, DC area, Mr. Farber.