a) Khun Paen Kluab (Enameled), Wat Yai Chai Mongkol, Ayuthaya ( kaolin / enameled)
b) Khun Paen Bai Phut Sa , Wat Yai Chai Mongkol ( baked clay, and lead/ tin-based alloy) c) Khun Paen Wat Ban Krang, Wat Ban Krang, Suphanburi ( baked clay )
d) Khun Paen Khai Pha, Wat Phra Roop, Suphanburi ( baked clay)
e) Khun Paen Kru Monthien, Ayuthaya ( baked clay )
f)  KhunPaen Kru Wat Ratchaburana, Ayuthaya ( lead/tin-based alloy)  

After a long years of my arguments and debates with Khun Paen amulet experts, now comes a summary that  Khun Paen Guman Thong assumingly has two origins:

1) It might come from the misinterpretation of the lotus bases of Khun Paen Khai Pha as a lying baby

2) The other source with more reliable evidences say that it comes from Khun Paen legendary biography that Guman Thong is Khun Paen's mighty son and often called by his father to perform miraculous activities. Since Guman Thong life and his mighty emerged from Buddhistic magics and Kathas, so his small figure is put underneath Lord Buddha image on Khun Paen Guman Thong amulet; in this case sometimes Lord Buddha image is subjectively interpreted as Khun Paen.   

Guman Thong amulets alone have been creating since early Ratanakosin period--nearly two hundred years, but Khun Paen Guman Thong are for nearly 60 years since the early 2490s. As told by a close disciple of LP Tae Kong Thong: LP Tae was once asked about Guman Thong figure appearing on an amulet underneath the Buddha lotus seat, LP Tae replies, " Whatever form of a Guman Thong might be, it doesn't matter at all--because the most important thing is that how the consecrator monks bless it. "