Here is what my '82 LS looks like .
The upper line is 12.5 inches long .
I'm the third owner, the lines were replaced before I took possession of this bike, so I don't know if this is the correct routing or not .
I just measured the length of the handlebars on the '82 and '83 LS, the '83 has low bars, the '82 has high bars .
Don't know if the bars on the '82 were replaced by a previous owner or not, don't look like they have been disturbed since the bike was assembled at the factory .
I'm betting that the line you have from Spiegler is for low bars .
From their site, they have numerous part numbers for LS line kits, but no length of the lines in the kit .
I'd give them a call tomorrow and explain the situation, usually they are quite helpful in resolving issues .
Good luck .
If you going to order lines from Spiegler and not sure what you need, send them the lines .
Here's a page from RealOEM, this is for my '83 LS, shows both high and low bars, so it looks like you could have either from the factory .https://www.realoem.com/bmw/enUS/showparts?id=0365-USA-08-1983-248-BMW-R65LS&diagId=32_0741