Featured Mammalian Rib Bone; Calendar or Map? Inscribed Both Faces

First, please forgive me if I've asked about this here before. My memory ain't what it once was.

This is about a foot (31cm) long, 2 inches (5cm) wide max, 148gm. I think it's probably from a water buffalo, but that's only a guess; I also believe it's SE Asian or Pacific Islander in origin. You'll note that the back side is seriously faded, while the front looks almost freshly done. There are a dozen or so more pics; close-ups of the details...just ask, I'll post 'em...an' I'll be happy to answer your questions about it.
The potential for it being a calendar lies in the area immediately below the image of a dwelling...the 2 sets of 6 insect-like vertical characters ranked diagonally upper left to lower right...12 total.
As far as it representing a map, that's more of a reach...the elaborate stick & shell constructs I've seen called maps made by Pacific Islanders bear no resemblance to this.

Perhaps it is in some way a history document which, would I think, needs a calendar reference within it. That 'document' aspect assumes there is information in all the horizontally arranged lines of characters. On the first side, there are 12, 6, an' 5 of those, from the top down. On the other side there are 15, 6, 6, 6 & 5 of them, top to bottom.

I doubt this is a tourist trifle...there's far too much effort in its creation for it to be made for a quick buck from a gullible bumpkin.

I'm not well-informed about the myriad cultures represented in the vast reaches of the South Pacific Ocean...but I've not heard of any having a well-developed written language, which is what seems to be inscribed here. I bare my ignorance without shame, trusting in your goodwill an' acceptance.

What have I got? Have any of you seen its like? Has it any archeological value? It was acquired way too many decades ago for me to recall where, or at what cost...but I'm a pretty much a US West Coast provincial, so probably somewhere in California.

As always, thanks for lookin'!

 

Indonesian house..

 

@Any Jewelry ......... right up ur ally ????

 

or ...better.......below

https://www.etsy.com/in-en/listing/...type=cs&ref=landingpage_similar_listing_top-6

.

 

too slow.................

 

Excellent work...and most helpful, komokwa!
Sincere thanks!

 

A souvenir Porhalaan, nicely made.

https://en.wikipedia.org/wiki/Porhalaan

Used together with:

https://en.wikipedia.org/wiki/Pustaha

Although this one may be gibberish to a real Datu.

 

Thank you, AJ...I had found your first wiki late yesterday...lots of good scoops about my bone!
How, please, do you spot 'souvenir' indicators on it?

 

The engraving of the house, which has no place on a real Porhalaan.
The house is of the type from the lake Toba area (Toba Batak), a favourite holiday destination with many souvenir stalls.

 

That all sounds perfectly reasonable...Thanks, AJ!