I've got a personal story of neglected sleep apnea to share.
Before I get into that, if you are one that can stick with losing the weight and keep it off then I say go out the 6 months and see if you can drop another 50 lbs. If you are just 'saying' you're going to do it but most likely won't, or you're likely to lose it and gain it back, then go get a sleep study. Not being a jerk here, just suggesting you make sure to be honest with yourself.
I have sleep apnea and I've struggled with weight all my life, I've been on CPAP for about a 1 1/2 years now and in that time I've lost over 100 lbs. It made a big difference for me. But my story is about my dad....
He's had sleep apnea for years, even when he was much thinner. He's 6'2" and around 280 now but used to be closer to 220, overweight but not horribly. He used to rattle the house when I was a kid but we didn't know at that time what sleep apnea was. A few years ago he got tested and got a CPAP but he didn't use it. To avoid the boring details, my dad had a stroke last week and is currently in a rehab hospital. He had other issues that helped lead to the stroke but one thing the docs were very concerned about was that he had extremely elevated CO2 levels in his blood and his brain was not getting enough oxygen carried to it. Since he wasn't breathing he didn't expel the CO2 from his lungs and it was absorbed into his bloodstream. My father's sleep apnea almost killed him, or at minimum was a large contributing factor to his stroke.
If you can be healthy and lose weight then rock on, brother. If not then get tested sooner than later, many people don't realize how serious sleep apnea can be.